In 1965, there was a power blackout that affected the entire north-eastern seaboard.

"While speculation for Thursday's blackout centered on Niagara Falls, N.Y., the actual cause of the 1965 incident was traced to the Sir Adam Beck Station No. 2 in Niagara Falls, Ont. Six days after the failure, Federal Power Commission investigators traced the problem to a single faulty relay, which triggered a series of overloads that overtook main trunk lines and caused power plants to shut down automatically."